If a display is so provided that information highly important to a user is made conspicuous among various pieces of information on a screen, the screen can be a user-friendly screen. Elements that affect the conspicuousness of information include color as well as size and layout. In general, a designer determines the color scheme of a screen to coordinate colors in such a manner that each piece of information that makes up a screen will be conspicuous at an appropriate level within the entire screen depending on the degree of importance of each piece of information.
However, the kinds of information and the number of pieces of information to be displayed on the screen vary from situation to situation. For example, in the case of a screen in a monitoring service system, the number of pieces of alert or warning information to be displayed on the screen increases in the event of an abnormal situation compared with the normal situation. In this case, the proportion of the area of a color assigned to the alert or warning information on the screen increases. Thus, if the kinds of information or the number of pieces of information to be displayed on the screen vary, the balance of conspicuousness of respective colors on the entire screen may break down. For example, suppose that the system designer assigns, to alert information, red color that stands out alone on the screen in the monitoring system mentioned above on the assumption that the alert information is highly importance to users. However, for example, if many pieces of alert information are displayed on the screen in the event of an abnormal situation, the proportion of red on the screen will become high, reducing the conspicuousness of red in terms of the entire screen.
The color scheme determined when the screen is designed cannot be changed in most cases after the product is completed. Although there is a case where a user may be allowed to customize the screen even after the product is completed, the user is required to carry out change operations point by point. Further, when a user with no knowledge of the color scheme and the screen design customizes the screen, the screen may not have an appropriate color scheme according to the degree of importance on the screen. Therefore, it is desired that the color scheme can be changed immediately in response to a change in situation on the screen so that information that makes up the screen always stands out according to the degree of importance to the user.
Described in Non Patent Literature (NPL) 1 is a technique for evaluating a method of setting a color and area of each piece of information when plural pieces of information different in priority are displayed on a screen. This technique can evaluate, as a so-called “visualization achievement” value, display appropriateness as the entire screen in consideration of the attention-getting degree and priority of each piece of information on the screen.
A technique described in Non Patent Literature (NPL) 2 is able to calculate the conspicuousness of each color used within a screen in an attractiveness evaluation model in which a characteristic attractiveness as the conspicuousness of a color alone and a heterogeneous attractiveness as the conspicuousness of a color compared with the other colors are considered together. This technique can calculate the conspicuousness of respective colors in consideration of the balance of the entire screen.
Described in Patent Literature (PTL) 1 is a technique for controlling the way of making a region conspicuous by giving a difference in color or hatching density according to the area or importance of the region in a document. The saturation or shading of a color as an element used to determine the conspicuousness of the color alone can be changed according to the area or importance of the region, enabling easy coloring.